1. Field of the Invention
The present invention is directed to an medical diagnostic imaging apparatus.
2. Description of the Prior Art
In medical diagnostic imaging apparatus, for example, computed or magnetic resonance tomography device, a region to be imaged in an examination subject is positioned in an imaging volume of the apparatus for producing images of this region. Particularly in a magnetic resonance tomography apparatus, wherein the imaging volume within an examination space is often surrounded by a closed housing except for an entry opening, positioning of the subject occurs with the assistance of a support device that is displaceable in at least one direction on which the examination subject is positioned. For example, a projector that projects an optical mark onto the examination subject, for example a patient, is situated in the region of the entry opening. Given an initial displacement event of the support device, the support device including the patient positioned thereon is initially controlled such that the optical marking on the surface of the patient marks a center of the region to be imaged. A remaining displacement distance of the support device into the imaging volume then derives from the known distance of the optical mark from the imaging volume. For definition of the center of the region to be imaged, the support device must be moved, possibly back and forth, until the optical mark hits the desired center. Since, moreover, the support device exhibits a comparatively low displacement speed, the aforementioned positioning procedure is comparatively time-consuming. For a computed tomography apparatus, a comparable positioning device is disclosed, for example, in U.S. Pat. No. 4,117,337.
Compared to the aforementioned positioning, German German OS 195 08 715 discloses a method and an apparatus for positioning a patient in a medical diagnostic imaging apparatus, wherein by the positioning sequences more dependably and faster. To that end, the region to be imaged is identified with a mark fixed to the patient. An image pick-up device outside the examination space, for example a video camera, acquires the mark fixed to the patient in an image. An image processing unit recognizes the mark in the image and determines the spatial position thereof. A control device determines a displacement path of the support device from the spatial position of the mark as well as from the known position of the imaging volume. The control device controls a corresponding movement of the support device along the aforementioned displacement path.
It is especially disadvantageous in the aforementioned apparatus that a complicated and expensive system containing an image pick-up device and an image processing unit with corresponding image recognition software is utilized. Further, the mark may possibly adhere differently as a consequence of different surface qualities of clothing or the skin of the patient, and a slippage of the mark is therefore possible. Moreover, an application of the mark, particularly on the face of the patient, is considered unpleasant by the patient.
It is an object of the present invention to provide a medical diagnostic imaging apparatus that allows a fast positioning and diminishes the aforementioned disadvantages of the prior art.
This object is inventively achieved by an imaging medical diagnosis apparatus that contains the following features: a support device for displacing an examination subject positioned thereon in at least one displacement direction; a control device for controlling the displacement of the support device; an actuation arrangement that is encompassed by the support device that is oblong with its longer dimension disposed in the displacement direction, and that is actuatable at points at least in displacement direction; and a setting device that interacts with the actuation device and that is connected to the control device for the positioning a prescribable region to be imaged in the examination subject in an imaging volume of the device by a displacement of the support device. The region to be imaged can be prescribed by an actuation of the actuation device at one of the points, the position thereof with respect to the oblong actuation device corresponding to the position of the region to be imaged within the examination subject in displacement direction.
After the examination subject has been placed onto the support device, the region to be imaged can be simply, intuitively and quickly prescribed by a person participating in the implementation of the diagnosis by actuating the actuation device at a point lying next to the region to be imaged, a following positioning event can be implemented fast and free of interruptions. The initially described, time-consuming positioning procedure upon employment of an optical projection is thus eliminated. Further, no marking needs to be applied to the examination subject for prescribing the region to be imaged. Moreover, the setting device is simple compared to an image processing unit and corresponding image recognition software, and thus can be economically implemented.
In an embodiment, the actuation device is arranged such that it is free from being covered by the examination subject. As a result, the actuation device can be actuated with free accessibly by the person participating in the implementation of the diagnosis without the examination subject having to be moved for this purpose.
In another embodiment, the actuation device has a spacial extent approximating the length of the examination subject along the displacement direction. As a result, any region to be imaged in the examination subject can be prescribed. No limitations as to sub-regions of the examination subject thus exist due to the actuation device.
In a further embodiment, the prescription device is fashioned such that positioning-relevant data are available with an actuation of the actuation device. As a result thereof, the positioning-relevant data are available immediately upon actuation, for example, at a higher-ranking control device, so that the control device is able, before the initial displacement to pre-calculate quantities relevant to the implementation of the diagnosis, taking the positioning-relevant data into consideration.
To that end, the actuation device can have a sensor field.
In a further embodiment, the actuation device is fashioned such that a marking is attachable to the points. As a result, the predetermined region to be imaged remains marked in visible fashion or for the person at the support device participating in the management of the diagnosis, so that a slippage of the examination subject, and thus of the predetermined region to be imaged, for example as a result of movements on the part of the examination subject, can be easily recognized.
In another embodiment, the setting device has an acquisition unit that is arranged at a part of the apparatus that is not displaceable together with the support device and is fashioned such that, given an initial displacement of the bearing device, a passage of the marking is acquired by the acquisition device and positioning-relevant data are available. As a result, the actuation device can be implemented as an exclusively mechanical or passive device, so that it needs no electrical energy supply.
In a further embodiment, the acquisition device and the marking are fashioned such that the acquisition device mechanically or optically acquires the passage of the marking. The mechanical or optical acquisition thereby guarantees a reliable acquisition in a simple way, even in an electromagnetically rugged environment as represented, for example, by the high static basic-magnetic field of a magnetic resonance tomography apparatus.
In another embodiment, the medical diagnostic imaging apparatus is a computed or magnetic resonance tomography apparatus. In particular, computed and magnetic resonance tomography apparatuses represent medical diagnostic apparatuses having a considerable acquisition cost, so that the aim is to operate such devices with an optimally high usage. An increase in the usage is achieved, for example, by shortening the examination time per patient is. As a result of the setting device, the positioning event per patient is shortened by about half a minute up to an entire minute, so that one to two additional patients can be examined per day. The term xe2x80x9ccomputed tomography apparatusxe2x80x9d encompasses x-ray and electron beam computed tomography apparatus as well as positron emission tomography apparatuses.